The invention relates to a flame-retardant coating for fiber materials comprising at least one film-forming binder and one flame retardant, and to the use of a flame-retardant coating of this type.
Fiber materials, for example in the form of textile sheets, such as fabrics for drapes, carpeting, covers for automobile seats, railroad seats, or covers for children""s beds, etc. composed of, for example, cotton, cellulose fibers, polyester fibers, polyethylene fibers, polyamide fibers, polypropylene fibers or fiber mixtures ignite readily in the event of a fire.
It is known that textiles can be treated with compositions of decabromodiphenyl ether and other flame retardants, such as antimony trioxide and alumina trihydrate in the form of aqueous dispersions, in order to render them flame-retardant. These coatings contain halogen and therefore are in many cases not usable, in particular for textiles with which children come into contact.
Many attempts have therefore been made to replace these halogen-containing products with halogen-free products. Examples of halogen-free products used hitherto to render textiles flame-retardant are the known ammonium and sodium salts of phosphoric acid.
Disadvantages of these products are that firstly they do not give a satisfactory flame-retardant effect on fiber materials, and secondly that their high water solubility means that they are very rapidly removed as a result of washing.
Compositions of this type based on ammonium polyphosphate have given a more favorable result in this context insofar as water solubility and the effectiveness of flame-retardant action is concerned, but these are still not completely satisfactory. For example, ammonium polyphosphate tends to become tacky (xe2x80x9cfroggy handxe2x80x9d) in the presence of moisture.
The object of the present invention is therefore to provide a flame-retardant coating for fiber materials which avoids the disadvantages mentioned and is as good as previous compositions with respect to flame-retardant action and also xe2x80x9cfroggy handxe2x80x9d and superior to these in terms of freedom from halogen.
This object is achieved by a flame-retardant coating for fiber materials of the type described at the outset, wherein this comprises melamine polyphosphate as flame retardant.
The melamine polyphosphate preferably has the formula (HMPO3)n, where M is melamine and nxe2x89xa72, in particular from 2 to 10,000.
Melamine polyphosphate is a polymer composed of melamine units and phosphate units, linked to form chains of varying length. The distribution of the melamine units and phosphate units may be regular or irregular, and they may, if desired, also have been polymerized within themselves. Derivatives of melamine, such as melem, melam and others, may also be present.
The properties of the melamine polyphosphate may vary within certain limits due to variations in its chain length and in the distribution and/or frequency of the melamine units and phosphate units.
Melamine polyphosphate is described in more detail in PCT/WO 98/45364, for example, where it is also termed melamine salt of polyphosphoric acid. The polymeric chain here is composed of (HMPO3)n units [where M is melamine] and nxe2x89xa72, in particular from 5 to 10,000.
Melamine polyphosphate is usually obtained by heating melamine pyrophosphate to constant weight under nitrogen at a temperature of 290xc2x0 C. or above (PCT/WO 98/08898).
It is preferable for the film-forming binder to be
homopolymers based on vinyl acetate,
copolymers based on vinyl acetate, ethylene and vinyl chloride,
copolymers based on vinyl acetate and on the vinyl ester of a long-chain, branched carboxylic acid, copolymers based on vinyl acetate and di-n-butyl maleate,
copolymers based on vinyl acetate and acrylates, and/or
copolymers based on acrylates,
vinyltoluene-acrylate polymers,
styrene-acrylate polymers,
vinyl-acrylate copolymers, and/or
self-crosslinking polyurethane dispersions.
It is particularly preferable for the film-forming binder to be polyvinyl acetate copolymers or polyacrylates.
It is preferable for the ratio between the amount of film-forming binder (100% strength) and melamine polyphosphate to be from (10 to 1) to (1 to 5).
It is particularly preferable for the ratio between the amount of film-forming binder (100% strength) and melamine polyphosphate to be from (5 to 1) to (1 to 3).
It is preferable for water, and also, if desired, conventional auxiliaries and additives, to be present as further components.
It is preferable for the auxiliaries and additives present to comprise dispersing agents, foaming agents, foam stabilizers, thickeners, fungicides and/or antifoams.
It is preferable for the fiber materials to be fabrics for drapes, carpeting, covers for automobile seats or for railroad seats, or covers for children""s beds, composed of cotton, cellulose fibers, polyester fibers, polyethylene fibers, polyamide fibers, polypropylene fibers and/or other fiber mixtures.
The novel flame-retardant coating is suitable for practically any conceivable fiber material, and its use is therefore not restricted to the abovementioned application sectors.
Finally, the invention also provides the use of the novel flame-retardant coating for producing flame-retardant fiber materials.
In each of the examples below, a flame-retardant coating is first produced, and a certain thickness of this is applied to the appropriate fiber materials and dried. Depending on the nature and composition of the flame-retardant coating and of the fiber material in the fabric the product may then, if desired, be foamed, dried or crosslinked.
The coatings were then tested to the following standards:
for fire protection regulations in buildings:
DIN 4102 Part 1
for automobiles: FMVSS 302
for railroads: DIN 54336.
The freedom from tack of the coatings applied was assessed visually after storage under appropriate temperature and humidity conditions.